High frequency magnetic components are used in many applications including computer data transmission, cable TV video, and interactive CATV, among others. These applications generally require transformers and inductors that operate efficiently in the frequency range from 5 MHz to 1 GHz and beyond. However, a problem with conventional magnetic components is that they are large and bulky in comparison to the circuits in which they operate.
Further, manufacturing techniques of magnetic components typically involve machine-winding techniques for large-cored magnetic components and hand winding for small-cored magnetic components. As operating frequencies increase, transformers and inductors typically decrease in size, having finer electrical wire and smaller magnetic cores; wire sizes of 42 gauge (0.075 mm in diameter) and core diameters of 2.5 mm are common. Machine assembly with these small cores is impractical. As such, hand winding of wire onto the magnetic core, hand assembly of the wound core on the mounting header, and hand soldering of the wire to header connectors is required. Because all of these operations require high levels of manual dexterity and are very time consuming, it is not uncommon for labor costs to represent 60–70% of the total product cost.
Some research has been performed in the area of microtransformers and micromachining using electroplating techniques to obtain very thick conductors and ferrite materials. However, since this research generally applies to sensors and higher power magnetic devices operating in lower frequency ranges, the research is generally not applicable or viable for high frequency applications.
In view of the above, there is a need for an innovative approach for manufacturing miniature high frequency inductors and transformers. The manufacturing approach preferably is automated so as to reduce manufacturing costs as well as reduce the size of high frequency magnetic components.